Photographic process



FLUORESCENCE OF Dec. 1, 1942. 'G. T. LANE EIAL 2,303,942

' PHOTOGRAPHIC PROCESS Filed Aug. 22, 1941 Fu l.

ALUMINUM FLUORESCENT ALUMINUM EMULSION SENSITIVE TO MATERIAL 11 GERDLILDT. LANE CLARENCE L.A.WYND

' INVENTORS BY MXQWCZZ A TTORNE YS Patented Dec. 1, 1942 PHOTOGRAPHICPROCESS Gerould '1. Lane and ClarenceL. A. Wynd, Rochester, N. Y.,assignors to Eastman Kodak Com- D y, Jersey Rochester, N. Y., acorporation of New Application August 22, 1941, Serial No. 407,959

2Claims.

This invention relates to the reproduction of engineering drawings andthe like and particularly to a method for reproducing exactly a drawinglayout, or design prepared or made on a rigid opaque support.

For many purposes it is desirable to have a. drawing made on an aluminumsheet or other rigid support which can be depended upon to holddimensions exactly and which is not unduly fragile. It is also highlydesirable to be able to make accurate copies of such drawings on work ortemplate material such as aluminum sheets, plywood and the like.

In many manufacturing industries and especially in the production ofaircraft and automobiles, full size layout drawings are made which afterapproval are transferred to template or work material such as sheetmetal, wood or fabric. This transfer was formerly made by hand and oftenrequired up to sixty days to make dimensioned copies for a singleautomobile model.

Transfer by hand is not only time consuming but obviously subject toerror. It has been proposed to obtain transfer by photographic copyingwhich requires considerable space, good lenses and accurate adjustmentfor correct magnification. Inasmuch as several factors in photographiccopying depend upon the operator it is clear that the copy is notnecessarily an accurate one.

In accordance with the present invention this transfer or reproductionis made by contact printing so that an exact copy necessarily resultsfrom the practice of the invention and the question of tolerances doesnot arise. This is made possible by creating on an X-ray permeableopaque support such as aluminum or wood a drawing or sketch in terms ofluminescent and non-luminescent areas. This drawing when placed incontact with a photographic layer carried on a suitable support willexpose the layer so that when it is processed an exact copy of thedrawing will be produced. The support for this layer is preferably thework or template material desired for use.

In accordance with the preferred form of the invention, the drawing ismade on an aluminum sheet coated with a suitable material such ascalcium tungstate lacquer which is rendered fluorescent andphosphorescent when excited by X-rays. This drawing is then placed incontact with a sensitized sheet and exposed to epipolizing radiationsuch as X-rays to which the drawing slightly expose the whole of thesensitive layer the added exposure brought about by the luminescence ofthe calcium tungstate provides sufllcient contrast for cleanreproduction of line drawings. This effect may be increased by-adjustingthe properties of the photographic emulsion, particularly by choosing anemulsion with a very high gamma or usingsuitable reducing formulas, sothat the print has clean, black lines and no objectionable overalldensity.

In the drawing Fig. 1 is a, view in perspective of the drawing to bereproduced and Fig. 2 shows the drawing being contact printed on asensitive layer.

As shown in Fig. 1 an X-ray permeable support H! such as aluminum isprovided with a drawing or sketch l I made with an epipolic materialsuch as calcium tungstate.

For reproducing the drawing l I it is placed in contact with a layer [2sensitive to the luminescence of the calcium tungstate when activatedwith X-rays. X-ray radiation from a suitable source I3 is then directedthrough the aluminum sheet l0 to give the layer l2 an epipolized exposurcorresponding to the outline defined by the calcium tungstate whichcontinues to phosphoresce for some time after exposure. When processedthe exposed layer [2 which is carried by a support l4 provides a work ortemplate sheet.

Instead of drawing with a fluorescent pencilv or ink, it is prefered tocoat the support III with a layer of fluorescent material and draw onthis surface with a material opaque to the light the materialfluoresces. The printing operation which is identical with the onedescribed above exposes the photographic layer wherever the lines of thedrawing do not shield the layer from the fluorescent light.

It is of course highly desirable that the drawing be in intimate contactwith the photographic layer during the exposure. This may beaccomplished in any desired way and a vacuum frame has been found to bewell suited for this purpose.

It will be evident the process of the present invention not onlyeliminates the immense amount of work involved when copies are made byredrafting but also eliminates the possibility of errors in dimensionsor in the omission of parts.

When it is remembered that, in the art to which the present invention isparticularly applicable, the sheets upon which the drawings are made andreproduced range in size up to six sheet is permeable. Although theX-rays will feet Wide y twenty feet 8. the Practical difllgraphictechnique will be appreciated.

Practice of the invention is, or course. not limited to th reproductionof engineering drawing and will be found useful in many instances whereaccurate reproduction is required, such as large maps. and where use 01'glass plates of the required size would introduce hazards to the safetyof the operators.

Since those familiar with X-ray photography are well aware oi the manyemulsions available and suitable for being exposed by the light emittedby the different fluorescent materials which may b employed forpreparing the drawing to be reproduced, it is believed to be unnecessaryto describe in this application the various possibilities. However, itmay be mentioned that the matte transfer film described and claimed inapplication Serial No. 397,093 filed June 7, 1941, by Gerould T. Lane isadmirably suited to receiving the exposure when calcium tungstate is thefluorescent material used in the process.

What w claim as new and desire to secure by Letters Patent of the UnitedStates is: v

1. The method of obtaining engineering drawings on opaque templatematerial which com- 2,303,942 culties involved in employing ordinaryphoto-- prises preparing the drawing on a rigid Z-ray permeable supportin terms of fluorescent and non-fluorescent areas, providing the opaquetemplate material with a pho aphic layer sensitive to the fluorescenceoi the material defining the drawing. placing said drawing'in contactwith said sensitive layer, directing x-rays through said support, anddeveloping the exposed layer.

2. The method of reproducing'drawings and the like which comprisesforming on a rigid. opaque, non-frangible sheet coated with a layerwhich is rendered fluorescent and phosphorescent when activated byX-rays, a design which is opaque to the light emitted by said layer.exposing said sheet to x-rays whereby said layer is activated, holdingsaid sheet while luminescent from such activation in contact with asheet 0! opaque template material carrying a layer which isphotographically sensitive to the luminescent light thus emitted,whereby the luminescent light impresses a latent image in said sensitivelayer except where such light is intercepted by said design, anddeveloping a visible image insaid sensitive layer.

GEROULD T. LANE. CLARENCE L. A. WYND.

